Sutures



Unie States Patent SUTURES La Vern E. Rlmkel and Richard J. Zielinski, Madison,

Wis., assignors to Air Reduction Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application April 28, 1955, Serial No. 504,670

13 Claims. (Cl. 206-633) This invention relates to surgical sutures of the proteinaceous type and, more particularly, to a method of improving the flexibility of such sutures and to the tubing fluids in which such sutures are packaged for shipment and storage preparatory to their use.

Proteinaceous sutures are customarily made of animal tissue, such as the submucosa of the small intestines of sheep which are prepared in the form of strands or threads. The sutures thus prepared are then conventionally packaged in glass tubes or other suitable containers having a suitable preserving and conditioning fluid called tubing fluid, and hermetically sealed. The sutures may be sterilized either before they are packaged, or, after packaging, depending upon the type of suture and tubing fluid used.

Tubing fluids are broadly classified in either of two groups called boilable and non-boilable. The boilable tubing fluids are inert to the suture even at temperatures considerably above the boiling point of water such that the tubed suture may be subjected to sterilizing temperatures, to sterilize either the suture or the tube in which it is contained, without damage. The non-boilable tubing fluids on the other hand, consist of fluids which deleteriously affect the suture at boiling temperature and thus do not permit sterilization of the sutures when tubed therein.

The proteinaceous type, or so-called catgut, surgical sutures in their original form are stitf and must be made pliable before use so that they may be easily handled by the surgeon. When packaged in the boilable tubing fluids which have substantially no softening effect on the sutures, a subsequent softening treatment is required after removal of the sutures from the tubes or containers, before they can be used. This has been done, for example, by soaking the sutures in a softening agent such as water, prior to use. However, the non-boilable tubing fluids contain ingredients which render the sutures immersed therein pliable, so that non-boilable type sutures are in condition for use as removed from the suture tubes or containers. This is a significant advantage in surgical applications since any delay or possible contamination, that might occur as a result of further softening treatment, is avoided. In addition, the suture tubes may be packaged in an outer container having a sterilizing liquid medium therein, such as shown in the A. B. Kennison United States Patent No. 2,470,494. This eliminates the need for sterilizing the outsides of the tubes at the time of use, thereby further increasing the utility of the non-boilable type sutures, which are thus available for immediate use, by the surgical team, from the package or container. The present invention is concerned with the non-boilable tubing fluids and with the methods of improving the flexibility of proteinaceous sutures tubed in such fluids.

Although the non-boilable tubing fluids heretofore used have been effective for the most part in rendering sutures reasonably flexible such as to be usable upon removal from the containers or tubes in which they are packaged, these sutures have been found in many instances, to kink,

2,796,984 Patented June 25, 1957 or acquire a set, during storage, particularly when they have been treated to modify their digestion characteristics, such as by chromic tanning, and are wound on a reel or spool prior to packaging. Also, it has been found that small whiskers or barbs are raised along these suture strands during use, referred to as fraying, which makes the manipulation of the sutures diflicult due to snag formations and the like. Such fraying also weakens the sutures and aggravates the wound produced in applying the suture. Present tubing fluids are incapable of preventing fraying and its attendant difficulties.

Accordingly, it is an object of the present invention, to provide means for improving the pliability characteristics of proteinaceous, or catgut, sutures packaged in nonboilable tubing fluids.

It is a further object of the invention to provide means for reducing the frayability of non-boilable catgut sutures.

In addition, non-boilable tubing fluids, although effective for softening the sutures, have also exhibited an objectionable tendency to cause swelling of the suture strands. Swelling of the suture strands is accompanied by a loss in tensile strength and a loss in specific tensile softening constituents of the non-boilable tubing fluids may be decreased to reduce the swelling of the sutures, such improvement is always accompanied by a corresponding reduction in the pliability of the sutures, thereby making the sutures unsatisfactory for handling by the surgeon. Up to this time, it has not been possible to avoid or diminish swelling without detrimentally affecting the desirable flexibility qualities of the sutures.

A further object of the present invention, therefore, is to provide an improved non-boilable, tubing fluid for proteinaceous sutures, and a method of treating such sutures, in which the tendency of the sutures to swell when packaged in such tubing fluid, is diminished while the relative flexibility of the sutures is increased.

We have found that these objectives may be achieved by adding a small amount of propylene glycol to the con ventional non-boilable, tubing'fluids, presently used. This agent is completely miscible with such tubing fluid mixtures and is non-toxic, such that it is well tolerated by the body tissues and produces no irritation in those tissues with which the sutures come into contact. Preferably the propylene glycol additive is used in amounts of less than 5% by volume of the total mixture, and more preferably, in concentrations ranging from 0.25% to 1% by volume, depending upon the particular tubing fluid used, and the particular size of the sutures to be placed therein.

The non-boilable tubing fluids commonly employed comprise mixtures of one or more alcohols, such as ethanol and propanol, with water, in which the water is eifective primarily as a softening agent. Ethanol also appears to have a softening effect, although to a lesser extent, and for this reason a lower water content is usually provided in ethanol-water mixtures. The amount of water used varies from about 2% to 30% by volume, depending upon the alcohol-water mixtures employed. Generally, the water content of ethanol-water-mixtures is from 2% to 10% by volume, and that of propanol-water mixtures ranges from about 5% to 30% by volume. The

preferred tubing fluids to which the propylene glycol is 3 present invention, such that little or no irritation of the skin tissue coming into contact with the treated sutures will result therefrom. The improved tubing fluid, containing propylene glycol. additive as described aboye, markedly: enhances the flexibility of the tubed sutures over' and. above thatv obtainable when only the usual amountsv of water or other known softening agents are used. The sutures. tubed'in such fluid, moreover, are characterized by a very significant reduction in frayability and. have less tendency to swell during storage. The novel tubing fluid'as described herein may be used either with the plain sutures or with sutures that havev been treated to resist digestion, such asby chrorn-ic tanning.

The maximum advantages of the present inventionarede'rived by selecting the proportions of thealcohol, water and-propylene glycol for each particular size of suture. The following table illustrates preferred tubing fluid mixtures, according to the present invention, for several sizes of sutures, plain and ch-rornic tanned:

Table 1.-'Tubi'ng fluid solutions for various. sizesof sutures Isopropyl Propylene Phenyl Alcohol Glycol M Size of cur-ic Suture Bcn- Distilled Water Plain, Ghro- Plain, Ghrozoate.

percent mic, percent mic, percent percent percent 95 95 .90 .90 0.02 Q. S. AD-1007 94 93 75 90 0.02 Q. S. AD 100 O 93 92 .75 .75- 0.02 Q. S. AD 100 a 92 91 50 75- 0.02 Q. S. AD 100% 91 90 .50 .50 0.02 Q. S. AD 100% 90 89 .25 50 0.02 Q; S. AD 100% 89- 88 .25 25 0. 02. Q. S. AD 100% 88 87 .25 .25 0.02 Q. S. AD 100% In Table I above, the sizes of the sutures are desig nated by the symbols 5/0; 4/0, 1, 2, etc. which are conventional designations. of the diameters of the sutures according. to The United States Pharmacopoeia, and correspond to specific dimensions listed therein. The sutures increase in size reading downwardly in Table I. In the preferred tubing fluid mixtures shown in Table I for the various sizes of sutures, the. amounts of propyleneglycol and of isopropyl alcohol are. as shown, in terms of percent by volume of the total mixture, and the balance of the mixtures is. water, except. for the. extremely small amount of phenyl mercuric benzoate which may be viewed as negligible for the purpose of determining the. fluid constituents. It will be noted in the tabulated data that a greater relative proportion of water is used in the. larger size sutures and that as the amount of water is increased, relatively smaller proportions of propylene glycol additive are used.

The tubing fluids described in accordance with the present invention are readily prepared by dissolving the desired amount of propylene glycol in a mixture of a suitable alcohol and a suitable softening agent, such aswater.

The sutures, in accordance with the present invention, are prepared in the usual manner. Thus, the sutures are placed in individual glassv tubes and dried in the usual way. The tubes are then'filled with an anhydrous hydrocarbon of high boiling point, such as high-flash naphtha,

suiticiently to cover the sutures, and heated to sterilize the gut. The hydrocarbon remaining is then poured off,

and the tube filled with the novel tubing fluid herein de-' scribed, while the sutures. are in a sterile condition, and the tube sealed. A small amount of a germicidal agent,

such as phenyl mercuric benzoate, may be added with. the tubing fluid and a suitable rust inhibitor such as sodium benzoate, approximately 0.6%, may also be added to the tubing fluid mixture when the sutures are packaged already swaged with steel needles. However, such additives do not limit or altec't the invention described herein 7 in any way.

It will be understood that the foregoing examples are merely illustrative of the present invention and that the invention is not limited thereto. Various modifications may be made without departing from the spirit of the invention as defined in the appended claims.

We claim:

1. As an article of manufacture, a sealed container having therein, in combination, a proteinaceous suture, a small quantity of propylene glycol dissolved in a tubing fluid having substantially no deleterious eiiect upon said suture at temperatures below sterilization, and a softening agent.

2. An article of manufacture according to claim 1 wherein said softening agent is water.

3. An article of manufacture according to claim 2 wherein said tubing fluid comprises a water soluble, monohydric aliphatic alcohol of from 1 to 4 carbon atoms.

4. An article of manufacture according to claim 3 wherein said water soluble, monohydric aliphatic alcohol comprises from to 98% by volume of the total mixture.

5. As an article of manufacture, a sealed. container having therein, in combination, a proteinaceous suture, a small quantity of propylene glycol dissolved in a propyl alcohol, and. water as a softening agent.

by volume of the total mixture.

9. An article of manufacture according to claim 8 wherein said propylene glycol is from 0.25 to 1.0% by volume ofthe. total mixture.

10. As an article of manufacture, a sealed container having therein, in combination, a proteinaceous suture and a homogeneous liquid mixture comprising a major amonntof isopropyl alcohol and a minor amount each of water and propylene glycol. 7

11. As. an article of manufacturea sealed. container having therein, in combination, a proteinaceous surgical suture. and a. liquid mixture comprising by volume 70% to 95% of isopropyl alcohol, 5% to 30% of water and 0.25% to 1% of propylene glycol.

12 The method of treating a proteinaceous surgical surture' which comprises contacting the suture with a tubing fluid containing dissolved therein, a small quantity of propylene glycol and water and subsequently sealing said suture and the solution in a container.

13-. The method of treating a proteinaceous surgical suture which comprises contacting the suture with a solution comprising, by volume from 70% to 95% propyl alcohol, 0.25% to 1% propylene glycol and the balance water, and subsequentlyseali-ng the suture and the solution ina container.

No references cited. 

1. AS AN ARTICLE OF MANUFACTURE, A SEALED CONTAINER HAVING THEREIN, IN COMBINATION, A PROTEINACEOUS SUTURE, A SMALL QUANTITY OF PROPYLENE GLYCOL DISSOLVENT IN A TUBING FLUID HAVING SUBSTANTIALLY NO DELETERIOUS EFFECT UPON SAID SUTURE AT TEMPERATURES BELOW STERILIZATION, AND A SOFTENING AGENT. 